Acetal-containing monomers



nited States Patent 3,539,157 Patented Sept. 22, 1970 ice US. Cl.260-485 4 Claims ABSTRACT OF THE DISCLOSURE Novel acetal-containingcompounds which are useful in thermosetting polymers and coatingcompositions are obtained by reacting a vinyloxy compound with apolymerizable ethylenically unsaturated hydroxyl-containing material.

This invention relates to novel acetal-containing compounds and polymersand the methods of preparation thereof, and more particularly to adductsof a polymerizable ethylenically unsaturated hydroxyl-containingmaterial and a vinyloxy compound which can be employed in producingthermosetting polymers and coating compositions.

Thermosetting coating compositions comprising crosslinked, long chaincopolymers, as for example, the acrylamide interpolymers as disclosed inUS. Pat. No. 3,037,- 963, are well-known and widely employed. Suchcopolymers usually contain a resinous backbone built up by vinyladdition polymerization. Along this backbone are spaced pendant chemicalgroups which are capable of further reaction to cross-link thecopolymers and thereby produce a cured or fused coating. A number ofpendants groups have been employed to provide such cross-linking sites,such as, for example, glycidyl, methylol, alkyl methylol, hydroxyl,carboxyl and urethane groups. Little interest, however, has been shownin polymers which utilize acetal groups as a means for obtainingcross-linking. Most developments in this area have been concerned withgeneral improvements of existing polymer systems, as for example, wheredihydropyran was used to prepare acrylic esters of2-hydroxytetrahydropyran in order to mask the carboxylic acid groups andimpart storage stability to copolymers containing carboxyl and glycidylgroups, as disclosed in Canadian Pat. No. 672,947. Virtually no use hasbeen made of such acetal groups as a primary means for cross-linking.

It has now been discovered that by reacting a vinyloxy compound with apolymerizable ethylenically-unsaturated hydroxy-containing material, anadduct is formed which, when interpolymerized with another ethylenicallyunsaturated monomer or monomers, provides cross-linking sites on theinterpolymer, the sites being pendant acetal groups. Coatings producedfrom such polymers possess excellent qualities of durability, adhesion,gloss and chemical and solvent resistance and may be cured attemperatures below those required for many conventional thermosettingcoating compositions.

In general, the acetal-containing compounds of this invention may berepresented by the formula:

where R and R are each hydrogen, an alkyl radical, an aryl radical, or acarbalkoxy radical; R is a divalent organic radical; R is hydrogen, analkyl radical, or an aryl radical; R is an alkyl radical or an aralkylradical; and R is an alkyl radical, an aryl radical or an acyl radical.

The groups represented by R and R include hydrogen;

alkyl radicals, preferably having 1 to about 6 carbon atoms, such asmethyl, ethyl and propyl radicals; carbalkoxy radicals, also generallyhaving about 2. to 6 carbon atoms such as carbomethoxy and carbobutoxyradicals; and aryl radicals such as benzyl, phenyl, methylphenyl and thelike.

The substituents represented by R in the above formula may be anydivalent organic radical which can link together the vinyl and acetalgroups of the compound. A preferred radical is a carbonyloxy-containingradical having the formula:

6 -RCOR where R is an alkylene radical of 0 to about 5 carbon atoms,such as methylene or propylene, and R" is an alkylene radical of 1 toabout 6 carbon atoms such as methylene, ethylene or propylene. R mayalso be an oxy-containing radical having the formula:

RI 0!RII where R is an alkylene radical of 0 to about 5 carbon atomssuch as methylene or propylene and R is an alkylene radical of 1 toabout 5 carbon atoms such as methylone or propylene or an alkyleneradical of 1 to about 6 carbon atoms such as methylene, ethylene orpropylene. Other groups which R can represent include arylene radicalsincluding alkarylene and arylalkylene, for example, phenylene,methylphenylene, benzylene, and the like; alkenylene, for instance,vinylene, 3-butylene, and linolylene; cycloalkenylene radicals such ascyclopentadienylene and Z-cyclobutynylene; as well as alkenylarylenegroups such as vinylphenylene. R may also be a substituted hydrocarbonradical, for example, a halo-substituted organic radical such astetrachlorophenylene, 1- bromo-2-difluoropropylene, or it may be anamino-substituted hydrocarbon such as amino-methylene,3-arninopropylene, and the like. Other substituted hydrocarbon radicalswhich may be included within the scope of the R substituent arecyano-substituted hydrocarbon radicals such as 3-cyanopropylene, as wellas hydroxy-substituted radicals such as hydroxypropylene orhydroxy-butylene.

R includes hydrogen, alkyl radicals of 1 to about 5 carbon atoms such asmethyl, ethyl, propyl, or butyl radicals; monovalent cycloaliphaticradicals such as cyclohexyl, cyclobutyl; aryl radicals including alkaryland arylalkyl, for example, phenyl, methylphenyl and benzyl and thelike; alkenyl, for instance, vinyl or aryl; cyclyoalkenyl radicals suchas cyclopentadienyl and Z-cyclobutenyl; as well as alkenylaryl groupssuch as the vinylphenyl radicals.

R includes alkyl radicals of 1 to about 10 carbon atoms such as methyl,ethyl, propyl, or butyl radicals; and aryl radicals of up to about 10carbon atoms, such as phenyl, phenylethylene, methylphenyl and the like.

R includes alkyl radicals of about 1 to 10 carbon atoms such as methyl,ethyl, propyl, or butyl radicals; acyl radicals such as acetyl,propionyl, butyryl and other similar radicals of up to about 10 carbonatoms; and aryl radicals including alkaryl and aralkyl radicals, forexample, phenyl, methylphenyl, benzyl, phenylethylene and the like,generally having up to about 10 carbon atoms.

The vinyloxy compounds essential in preparing the above-described novelcompounds of this invention may be represented by the formula:

where R R and R are each hydrogen, an alkyl radical, or an aryl radical;and R is an alkyl radical, an aryl radical or an acyl radical.

The groups represented by R R and R include hydrogen and radicals ofabout 1 to carbon atoms such as alkyl radicals including methyl, ethyl,propyl, or butyl radicals; monovalent cycloaliphatic radicals such ascyclohexyl and cyclobutyl radicals; aryl radicals including alkaryl andaralkyl, for example, phenyl, methylphenyl, benzyl, phenylethylene andthe like; alkenyl, for instance, vinyl, allyl, oleyl and the like;cycloalkenyl radicals, such as cyclopentadienyl and 2-cyclobutenyl; aswell as alkenylaryl groups such as the vinylphenyl radical. Thesesubstituents may also include a substituted hydrocarbon radical, forexample, a halo-substituted organic radical such as pentachlorophenyl or1-bromo-3-trichloropropyl; an amino-substituted hydrocarbon group suchas aminomethyl or 3-aminopropyl; a cyano-substituted hydrocarbon radicalsuch as 3-cyanopropyl; a carboxyl-substituted radical such as3-carboxylpropyl or a hydroxy-substituted radical such as hydroxypropylor hydroxybutyl.

R may be an alkyl radical of about 1 to 10 carbon atoms such as methyl,ethyl, propyl, or butyl radicals. Also included within this group areacyl radicals such as acetyl, propionyl, butyryl and other similarradicals, generally having up to 10 carbon atoms; and aryl radicals,including alkaryl and aralkyl, for example, phenyl, methylphenyl,benzyl, phenylethylene and the like, generally having up to 10 carbonatoms.

The hydroxyl-containing compound which is reacted with the vinyloxycompound may be any ethylenically unsaturated polymerizable materialcontaining both a hydroxyl group attached to a carbon atom in themolecule and a CH C or CH--CH- group. This reactant also preferablycontains, in addition to the hydroxyl group, a single CH C group interminal position, which group is activated by adjacent groups such ascarbonyloxy groups, namely,

or phenyl groups, as in styrene.

Especially useful hydroxyl-containing materials are the hydroxyalkylesters of unsaturated carboxylic acids in which the alkyl group has upto about 12 carbon atoms. This group includes acrylic acid andmethacrylic acid esters of ethylene glycol and propylene glycol, such as2- hydroxyethyl acrylate, Z-hydroxyethyl methacrylate, 2- hydroxypropylacrylate and 2-hydroxypropyl methacrylate. Combinations of these estersare also widely used. There may also be employed similar esters of otherun saturated acids, for example, ethacrylic acid, crotonic acid, andsimilar acids having up to about 6 carbon atoms as well as esterscontaining other hydroxyalkyl radicals, such as hydroxybutyl esters andhydroxylauryl esters.

In addition to esters of unsaturated monocarboxylic acids, there mayalso be employed the monoor diesters of unsaturated dicarboxylic acids,such as maleic acid, fumaric acid and itaconic acid, in which at leastone of the esterifying groups is hydroxyalkyl. Such esters includebis(hydroxyalkyl) esters, as Well as various alkylene glycol esters ofsuch acids and mixed alkyl hydroxyalkyl esters, such as butylhydroxyethyl maleate and benzyl hydroxyp-ropyl maleate. Thecorresponding monoesters, such as the mono(hydroxyethyl),mono(hydroxypropyl) and similar alkylene glycol monoesters of maleicacid and similar acids can also be used.

Other available hydroxyl-containing compounds include polymerizableprimary aliphatic alcohols having at least one terminal CH :C group suchas allyl alcohol and its alkyl and aryl derivatives, such as, forexample, methallyl alcohol or Z-phenylallyl alcohol; and polymerizablehydroxyl-containing ethers having at least one terminal CH C groupincluding the allyl ethers of glycol, such as, for example, ethyleneglycol monoallyl ether or propylene glycol monoallyl ether.

Preferred hydroxyl-containing compounds are hydroxyethyl methacrylate,hydroxyethyl acrylate, hydroxypropyl 4 rnethacrylate, butyl hydroxyethylfumarate, ethyl a-(hydroxymethyDacrylate, and butyl hydroxyethylmaleate.

The following reaction between Z-hydroxyethyl methacrylate and ethylvinyl ether is believed to be representative of the reaction to producethe acetal-containing compound:

CHz CCOOCHzCHtOH CIIz- CHOCH2CH3 CHz=CCOOCHzCHzO$HOCH2CHa CH3 CH3 Inpreparing the novel acetal-containing compounds of this invention, theabove-described reactants are simply mixed together, preferably withcatalytic amounts of a strong acid and a free-radical inhibitor. It isalso preferred to add the hydroxyl-containing compound to the vinyloxycompound in order to minimize the possibility of forming difunctionalproducts. The hydroxyl compound is usually added dropwise to thevinyloxy compound with stirring and cooling of the mixture, preferablyto temperatures below about 50 C.

It is especially preferred to employ catalytic amounts of an acid inpreparing the acetal-containing compound. Among the most useful are thestrong inorganic acids such as, for example, hydrochloric acid, sulfuricacid, phosphoric acid, nitric acid, boron trifluoride, aluminumtrichloride and magnesium chloride, as Well as various strong organicacids, such as, for example, para-toluene sulfonic acid, trichloroaceticacid and trifluoroacetic acid. The desired reaction can be effectedWithout the addition of any such acid, or in the presence of only a weakacid, but it is then necessary to heat the mixture to highertemperatures in order to obtain a commercially feasible rate ofreaction. When strong acids are utilized, however, excellent reactionrates can be obtained at temperatures of as low as about 25 C.

It is also preferred to utilize catalytic amounts of a free-radicalinhibitor during the reaction. Among the most useful are quinone,hydroquinone, and phenothiazine.

The polymers of this invention, comprising the above acetal-containingcompound and one or more other polymerizable ethylenically unsaturatedmonomers, are especially valuable when used in thermosetting coatingcompositions, as mentioned above. It appears that curing occurs byformation of bonds between the acetal groups, thereby linking togetherthe polymers. Additional crosslinking sites for the acetal groups can beprovided by employing monomers containing different pendant chemicalgroups, such as hydroxyl or carboxyl groups. Included among a widevariety of such monomers, as well as those serving solely as members ofthe polymer chain, are:

(1) Unsaturated carboxylic acid amides such as acrylamide andmethacrylamide, as Well as itaconic acid diamide, alpha-ethacrylamide,crotonamide, fumaric acid diamide, maleic acid diamide and other amidesof alpha, beta ethylenically unsaturated carboxylic acids containing upto about 10 carbon atoms. Other polymerizable amide monomers, such asmaleuric acid, and esters thereof, and its imide derivatives such asN-carbamyl maleimide may also be utilized. Especially useful are thesubstituted unsaturated carboxylic acid amides in Which the amide groupshave a hydrogen atom replaced by the structure:

l -CHOR1 Where R is selected from the group consisting of hydrogen andhydrocarbon radicals, such as methyl or ethyl radicals, and R is amember selected from the group consisting of hydrogen and a radicalderived by removing the hydroxyl group from a monohydric alcohol.Examples of such substituted amides are N-butoxymethylacrylamide,N-butoxypropylacrylamide, N-hydroxymethylacrylamide andN-hydroxypropylacrylamide.

(2) Hydroxalkyl esters of unsaturated carboxylic acids, in which thealkyl groups have up to about 12 carbon atoms, such as hydroxyethylacrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate andhydroxypropyl methacrylate, as well as combinations of these esters orsimilar esters of other unsaturated acids such as ethacrylic acid orcrotonic acid. Also available are the mono or di esters of unsaturateddicarboxylic acids such as maleic acid, fumaric acid and itaconic acidin which at least one of the esterifying groups is hydroxyalkyl, such asbutyl hydroxyethyl maleate or benzyl hydroxypropyl maleate.

(3) Mono and di olefinic hydrocarbons, such as styrene,alpha-methylstyrene, alpha-ethylstyrene, alphabutylstyrene,1,3-butadiene, 2-methyl-1,3-butadiene, 2- chloro-1,3-butadiene and2-bromo-l,3-butadiene and the like, as well as halogenated monoolefinichydrocarbons, such as alpha-chlorostyrene, alpha-bromostyrene, 2,5-dibromostyrene, chloroethylene, 1,1-dichloroethylene, fluoroethylene,1,1-difluoroethylene and the like.

(4) Esters or organic and inorganic acids such as vinyl acetate, vinylpropionate, vinyl butyrate, isopropenyl acetate, isopropenyl propionate,vinyl alpha-chloroacetate, methyl acrylate, ethyl acrylate, methylmethacrylate, ethyl methacrylate, dimethyl maleate, diethyl maleate,dimethyl fumarate, diethyl fumarate and the like.

(5) Organic nitriles such as acrylonitrile, methacrylonitrile,ethacrylonitrile, 3-octenenitrile, crotonitrile, oleonitrile, and thelike.

(6) Acid monomers such as acrylic acid, methacrylic acid, crotonic acid,3-butenoic acid, angelic acid, tiglic acid, and the like.

(7) Monomeric ketones such as isopropenyl methyl ketone, vinyl methylketone, and the like.

In general, it is preferred that the monomer utilized contains a singleCH =C group in terminal position, which group is activated by adjacentgroups such as carbonyloxy groups, namely or phenyl groups, as instyrene, and an especially preferred group of monomers includes ethylacrylate, methyl methacrylate, butyl acrylate, ethylhexyl acrylate,styrene, vinyltoluene, hydroxyethyl methacrylate, hydroxypropylmethacrylate, hydroxypropyl acrylate, hydroxyethyl acrylate, butylhydroxyethyl fumarate and butyl hydroxyethyl maleate.

The above-described polymers are prepared according to conventionalprocedures utilizing standard catalysts such as organic peroxides,including benzoyl peroxide, ditertiarybutyl peroxide, and cumenehydroperoxide and azo compounds, such as alpha,alpha-azobisisobutyronitrile, and chain-modifying agents, such as themercaptans.

Various materials may be used as solvents, including aromatichydrocarbons such as xylene, toluene, and other aromatic hydrocarbonsolvents, including the commercial products having boiling point rangesof about 160 to 210 C.; alcohols, such as butanol, methanol and similaralkanols; ketones, such as isophorone and ethyl butyl ketone; andesters, such as ethyl acetate and butyl acetate. The type of solventused in the polymerization is dependent mainly on the solubilityparameters for both the initial monomers and the final polymer andusually a mixture of solvents is employed, such as a butanol and xylenecombination.

The polymerization is typically carried out by admixing theacetal-containing compound, other monomer or monomers, and the catalystsand chain-modifying agent, if any, in the solvent, and refluxing theresulting solution for a time sufficient to obtain the desiredconversion. Ordinarily, the polymerization will be complete in about 4to 16 hours. It is often desirable to add the catalyst in increments asthe polymerization progresses, and good agitation and carefultemperature control are also desirable because of the rapid reactionrate and because the reaction is exothermic.

An alternative method of preparing the above-described polymers,utilizing the same vinyloxy compound, hydroxyl-containing compound andother monomers, as listed above, consists of first interpolymerizing thehydroxyl-containing compound with the other monomers, according to thepolymerization procedure outlined above, and subsequently reacting thispolymer with the vinyloxy compound. Acetal groups are formed by thisreaction, apparently as described above, and the resulting polymer isthus substantially equivalent to the polymer as prepared by theprocedure first mentioned.

The compositions described can be used as such to make clear films, butusually are used as a vehicle in compositions in which there isincorporated a pigment composition. Any conventional pigment can beused; which pigment composition may include, for example, titaniumdioxide, carbon black, talc, barytes, zinc sulfate, strontium chromate,barium chromate, ferric oxide, silica and other such pigments, as wellas color pigments such as cadmium yellow, cadmium red, phthalocyanineblue, chromic yellow, toluidine red, hydrated iron oxide, and the like.The enamels or coating compositions are produced by blending the vehicleand the pigment composition in accordance with well-known practice.

In ordinary usage of the coating compositions of this invention, theyare applied to the article to be coated, for example, by spraying or bysimilar conventional techniques, and then baked to form a hard, adherentfilm. Typical baking schedules include 250 F. for 60.

minutes to 450 F. for 10* minutes.

There are set forth below several examples which illustrate the natureand properties of both the novel acetal-containing compounds of thisinvention and the polymers containing such compounds. However, theinvention should not be considered as being limited to their details.All parts and percentages are by weight unless otherwise specified.

EXAMPLE 1 A mixture of 130.2 grams (1.00 mole) of hydroxyethylmethacrylate, 0.25 milliliter of concentrated hydrochloric acid and 0.5gram of hydroquinone was added dropwise over a period of 20* minutes to75.7 grams (1.05 mole) of ethyl vinyl ether, while the temperature waskept below 35 C. by external cooling. After the addition was complete,the mixture was stirred at room temperature for four hours, treated with3 grams of solid sodium bicarbonate and stirred for an additional 5hours. The mixture was then filtered and distilled after addition of 1.0gram of phenothiazine. There was obtained 187 grams (93 percent) of2-(1-ethoxyethoxy)-ethyl methacrylate, B.P. 60-90" C./ 0.05 mm. (mostlyat 60-70 C.), having a refractive index of 1.4305, and showing nohydroxyl band in the infrared.

EXAMPLE 2 An acetal-containing compound was prepared as above, but wasnot distilled. Instead, it was evacuated at room temperature for 5 hoursto obtain 193 grams (96 percent) of the monomer, refractive index1.4317, whose infrared spectrum did not show any hydroxyl group.

EXAMPLE 3 A mixture of 195 .0' grams (1.50 mile) of hydroxyethylmethacrylate, 0.5 gram of hydroquinone and 0.25 milliliter ofconcentrated hydrochloric acid was added dropwise over a period of 30'minutes to grams (1.50 mole) of isobutyl vinyl ether. The temperaturewas kept below 35 C. by occasional cooling. The mixture was stirred atroom temperature for 4 hours and treated with 20 grams of sodiumbicarbonate. Stirring was continued for an additional 5 hours, themixture was filtered and distilled to obtain 306 grams (89 percent) of2-(1-isobutoxy- 7 ethoxy)ethyl methacrylate, B.P. mostly about 85C./0.05

Analysis.-Calcd. for C H O (percent): C, 62.58; H, 9.63. Found(percent): C, 62.42; H, 9.55.

EXAMPLE 4 The materials and procedure of Example 1 were followed, exceptthat hydroxyethyl acrylate was substituted for the hydroxyethylmethacrylate. 2-(1-ethoxyethoxy) ethyl acrylate was obtained in 80percent yield, B.P. 58- 64 C./ 0.05 mm., index of refraction 1.4295. Themonomer showed a trace of hydroxy group and a strong band at 5.86microns and a medium doublet at 6.15 and 6.23 microns in the infrared.

Analysis.lndicated for C H O (percent): C, 57.43; H, 8.57. Found(percent): C, 57.84; H, 8.47.

EXAMPLE 5 The materials and procedure of Example 1 were followed, exceptthat hydroxypropyl methacrylate was substituted for the hydroxyethylmethacrylate. 2-(1-ethoxyethoxy)propyl methacrylate was obtained in 88percent yield, B.P. 6874 C./0.05 mm., refractive index 1.4298. Themonomer showed a trace of hydroxyl group, a strong band at 5.87 micronsand a medium band at 6.17 microns in the infrared.

Analysis.Calcd. for C H O (percent): C, 61.08; H, 9.33. Found (percent):C, 61.09; H, 9.56.

EXAMPLE 6 To a mixture of 1340 grams (3.0 mole) of 51.6 percent butylhydroxypropyl maleate (in xylene) and 1.5 milliliter of concentratedhydrochloric acid there was added dropwise over a period of /2 hour 216grams (3.0 mole) of ethyl vinyl ether while the temperature was keptbelow 40 C. by cooling. The mixture was then stirred at room temperaturefor 4 hours, then treated with 30 grams of solid sodium bicarbonate, andstirring was continued for an additional 8 hours. The mixture was thenevaporated at 0.1 millimeter and about 35 C., cooled and filtered. Therewas obtained 830 grams (95 percent) of 2-(1- ethoxyethoxy)propyl butylmaleate, refractive index 1.4476, showing no hydroxyl band, a strongband at 5.85 microns and a medium band at 6.15 microns in the infrared.

EXAMPLE 7 To a mixture of 595 grams (2.00 mole) of 73 percent butylhydroxyethyl fumarate (in xylene) and 1.5 gram of concentrated sulfuricacid there was added dropwise over a period of 45 minutes 151 grams(2.10 mole) of ethyl vinyl ether while the temperature was maintainedbelow 40 C. by cooling. After stirring the mixture at room temperaturefor 4 hours, it was treated with 20 grams of solid sodium bicarbonate,and stirring was continued for an additional 5 hours Xylene and othervolatile materials were removed by evacuating at 40 C. and 0.1millimeter and the residue was cooled and filtered to obtain 503 grams(87 percent) of 2-(1-ethoxyethoxy)ethyl butyl fumarate, having arefractive index of 1.4486, and showing no hydroxyl band, a strong bandat 5.85 microns, a medium band at 6.13 microns and one at 12.9 micronsin the infrared.

EXAMPLE 8 To 37.0 grams (0.51 mole) of ethyl vinyl ether, there wasadded dropwise with stirring 65.0 grams (0.50 mole) of ethyla-(hydroxymethyl) acrylate containing 0.1 milliliter concentratedhydrochloric acid and 0.25 gram of hydroquinone. The addition took 15minutes, and the temperature was kept below 35 C. by occasional cooling.The mixture was then stirred at room temperature for 4 hours, thentreated with 1.5 gram of solid sodium bicarbonate and allowed to standfor 8 hours. The mixture was filtered and the filtrate distilled with0.5 gram of phenothiazine to obtain 91 grams (90 percent) of 8 ethylu-[(l-ethoxyethoxy)methyl]acrylate, B.P. 53-60" C./ 0.05 mm. Theanalytical sample was obtained by redistillation, having a B.P. of 5056C./0.05 mm., a refractive index of 1.4311; showing no hydroxyl band, astrong band at 5.85 microns, and a medium band at 6.13

microns in the infrared.

Analysis.-Calcd. for C H O (percent): C, 59.38; H, 8.97. Found(percent): C, 59.28; H, 9.08.

EXAMPLE 9 In preparing a polymer of this invention, a reaction vesselwas charged with the following:

Parts by wt. Acetal-containing compound of Example 1 20 2-hydroxyethylmethacrylate 10 Methyl methacrylate 35 Ethyl acrylate 25 Ethylhexylacrylate 5 Acrylamide 5 Butanol 25 Xylene t-Dodecylmercaptan 2.5AZo-bis(isobutyronitrile) (catalyst) 0.8

The mixture was refluxed for 3 hours at temperatures between and C.,after which an additional 0.2 parts of catalyst was added and refluxingwas continued for another 2 hours. The resulting interpolymer solutionhad a percent solids content of 47.9 and a Gardner viscosity of Z Thecomposition was applied to a steel panel and baked for 30 minutes at 350F.

In order to qualitatively determine the extent of crosslinking of thepolymer, the cured film was rubbed with a cloth soaked in xylene, 40passes being made. In this test, any dissolving of the film isconsidered evidence of incomplete cross-linking. It was found that thepolymer of this example was entirely undissolved, indicating the extentof cross-linking to be virtually complete.

EXAMPLE 10 A polymer of this invention, prepared as in Example 9,comprised the following materials:

Parts by wt. Acetal-containing compound of Example 1 20 Methylmethacrylate 45 Ethyl acrylate 20 Acrylamide 5 t-Dodecyl mercaptan 0.1Azo-bis(isobutyronitrile) 1.0 Butanol 25 Xylene 75 The resulting producthas a percent solids content of 46.8 and a Gardner viscosity of X. Thepolymer system was tested as in Example 9 and cross-linking was found tobe excellent.

EXAMPLE 11 A polymer of this invention was prepared, as in Example 9,utilizing styrene as a monomeric material. The composition comprised thefollowing materials:

Parts by wt. Acetal-containing compound of Example 1 20Butylhydroxyethyl fumarate 1 0 Styrene 30 Methyl methacrylate 7 Ethylacrylate 25 Ethylhexyl acrylate 5 Acrylamide 3 t-Dodecyl mercaptan 0.5AZo-bis(isobutyronitrile) 1.0 Butanol 10.0 Xylene 90.0

The resulting product had a percent solids content of 45 and a Gardnerviscosity of R-S. Excellent coatings were produced therefrom.

EXAMPLE 12 A polymer of this invention was prepared, as in Example 9,utilizing a different acetal-containing compound. The compositioncomprised the following materials:

The resulting product had a percent solids content of 49.3 and a Gardnerviscosity of W-. The composition was applied to a steel panel, baked for30 minutes at 350 F. and tested as in Example 9. Completely satisfactorycross-linking was found to result.

EXAMPLE 13 A polymer of this invention was prepared, as in Example 9,utilizing styrene as a monomer. The composition comprised:

Parts by wt. Acetal-containing compound of Example 7 10 Butylhydroxyethyl fumarate Styrene 30 Ethylhexyl acrylate 25 Methylmethacrylate 30 Azo-bis(isobutyronitrile) 1.0 Butanol 10.0 Xylene 90.0

The resulting product had a percent solids content of 42.6 and a Gardnerviscosity of G-H. The extent of cross-linking was found to be virtuallycomplete.

EXAMPIJE 14 A polymer of this invention was prepared, as in Example 9,utilizing a different acetal-containing compound. The compositioncomprised:

Parts by wt. Acetal-containing compound of Example 6 20 Butylhydroxyethyl maleate Ethylhexyl acrylate 10 Methyl methacrylate 58Acrylamide 2 t-Dodecyl mercaptan 0.1 Azo-bis(isobutyronitrile) 1.0Butanol 10 Xylene 90 The resulting product has a percent solids contentof 45.9 and a Gardner viscosity of 5. Excellent coatings were producedtherefrom.

EXAMPLES 15-17 Three polymer systems were prepared, each utilizing adifl'erent acetal-containing compound selected from the group consistingof 2-(1-ethoxyethoxy)ethyl acrylate (Monomer A),2-(1-ethoxyethoxy)propyl methacrylate (Monomer B), 2-(1-isobutoxyethyl)ethyl methacrylate (Monomer C). The composition of each polymer systemcomprised the following materials:

Parts'by wt. Acetal-containing compound 20 Z-Hydroxyethyl methacrylatel0 Methyl methacrylate 37 Ethyl acrylate 25 Ethylhexyl acrylate 5Acrylamide 3 t-Dodecyl mercaptan 2.5 Azobis(isob-utyronitrile) 1.0Butanol 25 Xylene 75 The composition prepared using Monomer A had apercent solids content of 50.4 and a Gardner viscosity of NO; thecomposition prepared utilizing Monomer B had a percent solids content of51.0 and a Gardner viscosity of R-S; and the composition prepared usingMonomer C had a percent solids content of 50.4 and a Gardner viscosityof R. Each composition was applied to a steel panel, baked for 30minutes at 350 F. and tested as in Example 9. Excellent curing wasexhibited by each of the three polymer systems.

According to the provisions of the patent statutes, there are disclosedabove the invention and what are now considered to be its bestembodiments. However, it is to be understood that, within the scope ofthe appended claims, the invention may be practiced otherwise than asspecifically described.

I claim:

1. A novel acetal-containing compound having a formula selected from thegroup consisting of:

(1) 0112:0-0 OORzOOHORa 1 h C|H3 wherein R is H or CH R is ethylene orpropylene, and R is a lower alkyl radical, (2) R4OOOCH=OH-O OOR2OCHO-Rawherein R is a lower alkyl radical and R and R are as described above,and

( C O 0 R5 CH3 wherein R is a lower alkyl radical and R is as describedabove.

2. The compound of claim 1 which is a member selected from the groupconsisting of 2-(1-ethoxyethoxy) methacrylate; 2-(1-ethoxyethoxy)ethylacrylate; 2-(1- ethoxyethoxy)propyl methacrylate and2-(1-isobutoxyethoxy) ethyl methacrylate.

3. The compound of claim 1 which is 2-(1-ethoxyethoxy)propyl butylmaleate.

4 The compound of claim 1 which is 2-(1-ethoxyethoxy)ethy1 butylfumarate.

References Cited UNITED STATES PATENTS 2,458,888 1/ 1949 Relrberg et a1260-83 3,022,292 2/1962 Sims 260485 3,391,183 7/1968 Dowbenko 260-4 853,414,632 12/1968 Edwards et al. 2604'85 OTHER REFERENCES Theilheimer I,Syn. Methods of Org. Chem., (1949), vol. 3, p. 69.

Theilheimer II, Syn. Methods of Org. Chem., (1954), vol. 8, p 76.

LORRAINE A. WEINBERGER, Primary Examiner E. J. SKELLY, AssistantExaminer US. Cl. X.R.

